Abstract
Following COVID-19 exposure, the Centers for Disease Control (CDC) recommends a 10–14-day quarantine for asymptomatic individuals and more recently a 7-day quarantine with a negative PCR test. A university-based prospective cohort study to determine if early polymerase chain reaction (PCR) negativity predicts day 14 negativity was performed. A total of 741 asymptomatic students in quarantine was screened and 101 enrolled. Nasopharyngeal swabs were tested on days 3 or 4, 5, 7, 10, and 14, and the proportion of concordant negative results for each day versus day 14 with a two-sided 95% exact binomial confidence interval was determined. Rates of concordant negative test results were as follows: day 5 vs. day 14 = 45/50 (90%, 95% CI: 78–97%); day 7 vs. day 14 = 47/52 (90%, 95% CI: 79–97%); day 10 vs. day 14 = 48/53 (91%, 95% CI:79–97%), with no evidence of different negative rates between earlier days and day 14 by McNemar’s test, p > 0.05. Overall, 14 of 90 (16%, 95% CI: 9–25%) tested positive while in quarantine, with seven initial positive tests on day 3 or 4, 5 on day 5, 2 on day 7, and none on day 10 or 14. Based on concordance rates between day 7 and 14, we anticipate that 90% (range: 79–97%) of individuals who are negative on day 7 will remain negative on day 14, providing the first direct evidence that exposed asymptomatic students ages 18–44 years in a university setting are at low risk if released from quarantine at 7 days if they have a negative PCR test prior to release. In addition, the 16% positive rate supports the ongoing need to quarantine close contacts of COVID-19 cases.
Highlights
Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the novel coronavirus SARS-CoV-2, first reported in Wuhan, China, on 12 December 2019 [1]
Given the limited data supporting these recommendations, the need to understand the applicability for students in the university setting, and the negative financial, emotional, and logistical impact of an extended quarantine period [10], the purpose of this study was to test the hypothesis that consistent testing throughout the quarantine period might reliably predict day 14 outcome and could be used to determine if asymptomatic students might qualify for a shortened quarantine duration
Of the other contact measures, only unmasked exposure time appeared to influence the risk of transmission, with only 6% (1/18) of individuals exposed for less than an hour developing an infection. This is the first prospective study of students in a university setting assessing a testing strategy to predict day 14 positivity to evaluate the safety of shortened quarantine recommendations for young adults
Summary
Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the novel coronavirus SARS-CoV-2, first reported in Wuhan, China, on 12 December 2019 [1]. COVID 2022, 2 the case fatality rate is approximately 1% [1,2], making COVID-19 more pathogenic than seasonal influenza pandemics with a case fatality rate of approximately 0.01% [5]. Since effective pharmacological interventions are limited, public health measures including social distancing, isolation, and quarantine are employed to limit spread of the virus, reduce infections, and prevent deaths. Quarantine separates asymptomatic individuals who have had contact with a COVID-19 case [6]. There are no prospective studies demonstrating the benefit of quarantine to prevent COVID-19 infections. A recent Cochrane review includes modeling studies that consistently suggest isolation of infected individuals and quarantine of contacts is beneficial, with 44–88% of cases averted and 31–63% of deaths, the authors rated the evidence of certainty as low [7]. Additional prospective studies, especially in university settings, are warranted so that informed decisions can be made with regard to quarantine status of students
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